Following two messages were displayed 5 times while installing was in progress.../.local/share/Ryzom/ryzom_live/ryzom_configuration_qt: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version `GLIBCXX_3.4.21' not found ...

.../.local/share/Ryzom/ryzom_live/ryzom_configuration_qt: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version `CXXABI_1.3.9' not found...

After them, following two messages was displayed 10 times while installing was in progress

.../.local/share/Ryzom/ryzom_live/ryzom_client: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version `GLIBCXX_3.4.21' not found ...